Commercial nuclear reactors are capable of producing energy with no significant emissions into the atmosphere. However, nuclear reactors generate radioactive spent nuclear fuel (SNF), which following power generation are no longer capable of sustaining a fission chain reaction due to a build-up of neutron-absorbing fission products called poisons. For re-introduction back in the reactor for further power generation, spent fuel must be recycled by separating the remaining uranium fuel from the neutron-absorbing fission products. Recycling can maximize nuclear fuel utilization and reduce waste.
Various techniques can be used to recycle spent nuclear fuel. PUREX (Plutonium-Uranium-Extraction) is an accepted standard aqueous (wet) reprocessing method for the recovery of fissile uranium and plutonium from nuclear fuel. PUREX is based on dissolving the fuel in acid and utilizing liquid-liquid extraction to separate the uranium and plutonium from fission products. Pyroprocessing is another recycling technique whereby a high-temperature molten salt, for example LiCl+KCl, is used as an electrolyte in an electrochemical extraction of uranium and plutonium. Some efforts have been done to recycle spent nuclear fuel using a dry recycle process, for example the process described in U.S. Pat. No. 5,597,538. Concerns about the possibility of extracting plutonium, the use of toxic chemicals, and the large volumes of radioactive liquid and gaseous waste associated with these recycle methods has led to an alternative method known as dry recycling which avoids these negative features. Dry recycling does not extract plutonium or use toxic chemical additives or generate large volumes of radioactive liquids. Generally, dry recycling only requires fresh enriched uranium oxide feed material (20-30% volume and 17 wt % enriched uranium oxide) to be mixed with the existing spent fuel in order to overcome effects of residual neutron absorbing fission products, primarily rare-earths. The fresh feed+spent fuel mixture is a viable nuclear fuel for further power generation. The fresh feed requirements can however be significantly reduced by the removal of the neutron absorbing fission products. Therefore there is a need for the extraction of the rare-earth fission product poisons and consequently a significant reduction in the fresh feed volume fraction and enrichment resulting in enhanced economic viability as well proliferation and environmental attractiveness.